1. Field of the Invention
This invention relates to a surgical instrument and more particularly to an instrument for use during laparoscopic or endoscopic surgical procedures.
2. Brief Description of the Prior Art
Laparoscopic/endoscopic surgery is a relatively new operating technique that has been developed to carry our minimally invasive surgery and more especially cholecystectomy (gallbladder removal). It can also be used in gynecology, neurosurgery, urology and other general surgical procedures.
In general, this technique is much less invasive than a conventional surgery. It involves puncturing the abdominal wall and inducing a pneumoperitoneum to distend the abdomen. A trocar of about 5 to 10 mm in diameter is inserted into the puncture and used as a guide through which one or more surgical instruments may be inserted and guided with great accuracy towards the body part requiring surgery. Such surgical instruments may include an endoscope (laparoscope), a clip applier, microscissors or forceps, an optical fiber connected to a laser source for hemostatic cutting or coagulation, a set of electrodes connected to a generator for electrocautery, etc . . . If desired, one or more smaller trocar may be inserted into the 5 to 10 mm trocar to work with two or more instruments.
Following the surgery, the puncture may be closed in a very simple manner, using a sterile suture or adhesive strip to do so. This reduces to a minimum the patient's stay at the hospital and the period for his or her recovery and resumption of normal activity. It also reduces the post-operation scar.
During surgery, it is often required to irrigate inside the abdomen with a irrigation fluid, e.g., a saline, or to suction the internal body cavity which may be, for example, the bowel or the gallbladder, without having to stop the surgical step that is being carried out. It is also required to evacuate stones or blood clots from the cavity.
Generally it is preferable to have as few punctures made in the patients' body as possible. One way of achieving this is to have both irrigation and evacuation conducted along a single conduit which, in turn, can act as an access line for surgical instruments and/or a surgical instrument itself.
A typical device which is used in laparoscopic procedures is an electrosurgical probe. Typically such a probe will comprise an radio frequency energy conductive tube covered with a dielectric material such as polyolefin or Kynar.RTM.. At one-end, for convenience called the operational end, each probe could have any one of a number of functionally shaped electrodes. In addition a probe could have its end formed specifically for irrigation and/or evacuation.
As the electrodes at the end of the probe are not necessarily symmetrical about the longitudinal axis of the probe, it is desirable for the probe to be mounted on its supporting instrument to permit rotation thereof about this axis. This would allow the manipulation of the operational end of the probe without unnecessary and inconvenient movements of the surgeon's arm. In addition, as a variety of electrode shapes are available to the surgeon it is desirable for these probes to be interchangeable.
Furthermore, any valves controlling the evacuation and irrigation procedures should be constructed so as to minimize the possibility of the valve malfunctions if, for example, any tissue or blood coagulates around their moving parts. Similarly if any of the instrumentation is to be reusable, such instrumentation, including the valves, should be capable of being efficiently sterilized or cleaned by, for example, flushing.
In many of the devices used, the irrigation fluid is supplied under pressure to the surgical instrument. This is done by providing some form of pressurizing device (e.g. a pump) between the supply reservoir, in which the irrigation fluid is stored, and the surgical instruments. This type of pressurizing device has the disadvantages of being expensive, inconvenient difficult to adjust irrigation fluid supply rates with and usually located remote from the surgeon performing the surgical procedures.
The need is, therefore, for a surgical tool which, in one way or another, meets the above requirements and overcomes the problems of the prior art.